[mtr33]

I would like to take a stab using a quick study of M. Rossman GSEM work from TGM in the Biomechanical Integration Approach.

1L-5 and 1L-6 are geometric ideals based upon the design and engineering of the golf club combined with the kinesiology of our machine. (my words, probably wrong )

Our biomechanics must COMPLY with the geometry, not create it in this case. The movements used to comply are to be learned by studying both bio-mechanics and Kinematics, if so inclined. I'm just sticking with the Yellow book until I have that mastered in my fourth lifetime.
Kevin

Appreciate the effort Kevin. I wish I could get my hands on that BIA book. Too bad shipping it to the EU is quoted as twice as expensive as the book itself. Sounds like an interesting read (provided you have a more than average medical background). But then again, TGM sometimes requires advanced physics.

Regarding the quote you found, I don't think this alone substantiates the TGM definition of "on-plane" as such. Could you give more details on 1L-6 (which is a schematic drawing i guess)? The reasoning WHY the 1L-5/6 positions are "natural", given the designs of the club and our kkinesology, would be interesting and could provide the answer I'm looking for.

@HungryBear:
Right, there is no single 2D plane for the clubshaft throughout the swing. A "TMG-on-plane-swing" includes plane-shifting of the shaft during the swing (don't you just love confusing definitions ).